1. Field of the Invention
This invention relates to an antenna and more particularly to an antenna for a portable, wireless communication device having a unique sheath design.
2. Description of the Related Art
Antennas for portable, wireless communication devices such as two-way radios, cellular telephones, etc., normally include a thermoplastic or rubber sheath which encloses the mechanical components of the antenna. In most cases, the conventional antenna includes an electrically conductive connector positioned at the base of the antenna for connection to the circuitry of the radio. The conventional antenna normally also includes at least one helical radiating antenna element electrically connected to the connector and which extends therefrom. In many cases, a pair of series-connected, helical radiating antenna elements are employed. The length of the helical radiating antenna elements is determined by the frequency of the antenna. Thus, when a manufacturer produces antennas having various frequencies, it is necessary for the manufacturer to have a large number of different antennas in inventory, since the sheaths for the antennas are normally manufactured to accommodate specific antenna elements having a particular frequency. Further, the conventional antennas normally employ a cap which is secured to the tip end of the antenna for sealing the interior of the antenna. One reason why conventional antenna sheaths employ a cap at the tip end thereof is to facilitate the assembly of the antenna. However, the cap, which is bonded onto the tip end of the antenna sheath, sometimes becomes loose resulting in field failure.